stu_python = {"zeno","小白","小黑"}
stu_c = {"zeno","小白","小蓝"}

# 1.求出即学了python又学了c++的(共同的元素)  --交集&
print(stu_python&stu_c)
# 2.求出学了python或者是c++的(包含python和java的每一个元素)   --并集|
print(stu_python|stu_c)
# 3.求出学了python但是没有学c++的
print(stu_python-stu_c)
# print(stu_java-stu_python)
